Magnetrons, as an important kind of high power microwave devices, have a wide range of applications in many fields, such as military, medical and civil fields. As one of the key components of the magnetron, the cathode plays an important role in the operation of magnetrons. In order to develop high-power and high-frequency magnetrons, the cathodes are needed to have a certain thermionic emission and excellent secondary electron emission properties. Currently, Ba—W dispenser cathodes are generally used in the commercial magnetrons. However, Ba—W dispenser cathodes can not fulfill the requirements of the high power magnetrons due to their bad anti-bombarding insensitivity and poor secondary emission yields. It has been shown that REO-Mo cathodes exhibit an excellent secondary emission property and good anti-bombarding insensitivity. However, their low thermionic emission current density still limits their applications in the high power magnetrons. Therefore, there remains a need for developing a new type of cathodes possessing all desired properties for high power and millimeter-wave magnetron applications.